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Abstract

Viral pathogens pose an emerging threat to the sustainability of insect mass-rearing systems, yet they remain understudied in key species like the black soldier fly (BSF; ). Although multiple viral sequences have been reported in BSF, their role in disease has not been established until now. Here, we provide the first characterization of solinvivirus (HiSvV), confirming its role as a viral entomopathogen of BSF. Metatranscriptomic analysis of a diseased colony revealed a high viral load attributable to HiSvV. We successfully isolated the virus and developed injection- and oral-based infection assays to investigate replication, tissue tropism, transmission and risk of mortality. HiSvV replicated in inoculated adults, induced premature mortality in flies and was transmitted both horizontally and vertically. Infected flies also mounted a broad antiviral response, which supported active pathogenesis, even if the small RNA pathways were not activated. These findings establish HiSvV as the first confirmed viral pathogen of BSF and underscore the urgent need for viral surveillance and experimental tools to safeguard industrial insect rearing.

Funding
This study was supported by the:
  • H2020 Marie Skłodowska-Curie Actions (Award 859850)
    • Principal Award Recipient: ÉlisabethA. Herniou
  • H2020 Marie Skłodowska-Curie Actions (Award 859850)
    • Principal Award Recipient: SalvadorHerrero
  • MCIN/AEI/10.13039/501100011033 (Award TED2021-130679B-I00)
    • Principal Award Recipient: SalvadorHerrero
  • European Union NextGenerationEU/PRTR (Award TED2021-130679B-I00)
    • Principal Award Recipient: SalvadorHerrero
  • Agence Nationale de la Recherche (Award ANR-24-CE20-6083)
    • Principal Award Recipient: ÉlisabethA. Herniou
  • This is an open-access article distributed under the terms of the Creative Commons Attribution License. This article was made open access via a Publish and Read agreement between the Microbiology Society and the corresponding author’s institution.
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2026-03-02
2026-03-14

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